#include <stdio.h>

char *MyStrstr(char *s1,char *s2)
{
    for(int i = 0; s1[i] != '\0'; i++)
    {
        int flag = 0;
        for(int j = 0; s1[j] != '\0'; j++)
        {
            if(s1[i + j] != s2[j])
            {
                flag = 1;
                break;
            }
            if(flag == 0)
            return (char *)(s1+i);
        }
    }
    return NULL;
}

int main()
{
    char p1[] = "hello";
    char p2[] = "l";
    char *p = MyStrstr(p1,p2);
    printf("%s\n",p);
    return 0;
}